1. Field of the Invention
The present invention relates to an auto-focusing (AF) zoom lens mechanism, and in particular to an auto-focusing zoom lens mechanism having one step motor unit driving a zoom lens unit and an AF lens unit.
2. The Related Art
In general, a conventional auto-focusing (AF) zoom lens mechanism has two step motors. One of the step motors drives a zoom lens unit to achieve the function of zoom, and the other drives an AF lens unit to achieve the function of AF.
The auto-focusing zoom lens mechanism has to provide at least two step motors. The structure of the auto-focusing zoom lens mechanism is very complex, so that it is very difficult to assemble and it is not convenient to use. Furthermore, The auto-focusing zoom lens mechanism utilizes two step motors to drive the zoom lens unit and the AF lens unit, respectively. It is difficult to operate these step motors synchronously. Therefore, the operation of the auto-focusing zoom lens mechanism is not precise and hard to take a clear image.